Use this tool to calculate the approximate amount of grout needed to complete your job. Coverages provided are approximate and are for estimating purposes only.
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Square Edge / Rectified & Rectangular Tile Installation Guidelines
The new TCNA (Tile Council of North America) Handbook addresses the grout line size issue by recommending that the width of the grout joint be determined by the ANSI A108.02 specification which states that the actual grout joint size shall be at least 3 times the actual variation of facial dimensions of the tile.
The 2012 TCNA Handbook shows a chart that reads; Pressed Floor and Porcelain Tiles in sizes larger than 12X12 should have a Joint Width of 1/4” or greater and having Allowable Lippage of 1/16”. The typical standard for most Square Edge / Rectified tiles, regardless of size, says that installations shall have a grout joint width no less than 3/16".
Manufacturers no longer recommend that large format Rectified and Non-Rectified rectangle sizes (Example: 12" x 24") be installed in a brickwork or running bond pattern where the overlap or joint offset is 50%.
The reasoning behind this is that the allowable warpage or camber (crown) for a tile based on ANSI specifications can create an installation issue (lippage) when large format rectangular tiles are installed in a brickwork/running bond pattern. This allowable warpage can create a scenario where lippage is inevitable given the overlapping pattern.
The Industry Standard Statement at this time is: To mitigate this effect a new installation pattern that will be referred to as a "Staggered" brickwork pattern where the overlap is less than 33% and should have a grout joint width be a minimum of 3/16".